Isuzu's N-Series trucks have been at the forefront of industrial and company applications since its introduction as the N-Series in 2004 and before that as the Elf series. A 60-62 percent Philippine market share and a number one ranking (total sales) in the Japanese domestic market for 38 straight years shows its popularity within the industrial sector, mainly attributed to the massive diesel engines required to pull their 3.5 to eight tons of gross vehicle mass, displacing from 2.8 liters to 4.6 liters.

But what people don't know is that while these lumbering land movers can deliver heavy cargo from point A to point B quickly, they also can run the farthest on little diesel fuel. Recently Isuzu took a select number of motoring journalists and corporate clients to the Batangas Racing Circuit (BRC) to prove the said maxim.

How to drive a truck and save fuel

According to recent studies provided by Isuzu Philippines Corporation, fuel costs constitute 72.4 percent of the three main transport costs (fuel, tires/batteries, and maintenance) of any vehicle, whether for personal or corporate use. This use of fossil fuel for transport purposes releases a number of gases as by-products of engine combustion, the biggest being carbon dioxide or CO2 (94.1 percent, according to recent studies by Japan's National Promotion Center of Global Warming Prevention Efforts), and resulting (at the current rate) in acid rain, severely polluted air in large cities and global warming. The transport sector is the third biggest source of CO2 emissions (20 percent, with the industrial and energy conversion blocs far ahead at 30-31 percent), with trucks being the second biggest source of CO2 transport emissions (30 percent, with passenger cars far ahead at 54 percent). "These reasons are why Isuzu recommends fuel saving driving to reduce costs, to operate safely (being fast doesn't necessarily mean driving safe) and to protect the environment by reducing fossil fuels consumed," said Isuzu Philippines Corporation (IPC) service and quality assurance (service and publication section) instructor Heinz Lim.

With that in mind, IPC gave motoring scribes and fleet clients present at BRC the opportunity to drive two of the N-Series trucks the 3.5-ton NHR (in 12-17-seater form) and the six-ton NPR (in dump truck form) in normal driving conditions, with a speed limit of 50 kph and each truck given a payload equivalent to its aforementioned weight. Each participant was to drive around BRC's long course using either one of the N-Series (determined by drawing lots) with a marshal riding shotgun, stopping fully at certain parts of the course to record the fuel consumed by each driver upon arrival. "The fuel that each driver consumes is registered and recorded by a flow meter attached to the intake line of the vehicle and the fuel tank, down to the last cubic centimeter. The distance traveled between each stop simulates different driving conditions, such as highway, city, mixed and suburban driving," said Lim.

The fuel consumption and fuel mileage per attendee were then computed and displayed to the participants. After that, attendees were given tips on how to drive safely while saving fuel, such as shifting to a higher gear (using a 1500rpm upshift point, given the high torque nature of diesel engines) quick and early, driving at a constant speed, avoiding long idling and using the engine brake effectively instead of putting the manual transmission in neutral during downshifts. "We want you to achieve optimum fuel efficiency, considering that fuel costs keep increasing these days, aside from showing you the efficiency and fuel economy of Isuzu light duty trucks," said Isuzu Motors Limited (Japan) engineering support manager Hiroyuki Ishizuka.

Participants then drove around BRC again, this time using the fuel saving tips provided by Isuzu. Then the first and second round fuel consumption results were averaged and IPC computed each participant's percentage improvement in fuel economy. Attendees who drove the NHR "schoolbus" averaged a 44.32 percent progress in fuel economy rates, and those who drove the NPR "dump truck" averaged a 22.97 percent upswing. The highest improvement in the NHR category was a 59.09 percent jump by Auto Review's Ronald de los Reyes, from 6.64 kilometers per liter (km/l) to 16.24 km/l. The best improvement in the NPC category was a 38.78 percent progress by Top Gear editor-in-chief Vernon Sarne, from 8.56 km/l to 13.97 km/l. On the other hand, the corporate client with the best fuel consumption improvement was DHL's Cris Labis (who drove the NHR), with a 53.88 percent improvement.